See blog post 'Speed trick: Assigning large object NULL is much faster than using rm()!':
http://www.jottr.org/2013/05/speed-trick-assigning-large-object-null.html /Henrik On Tue, Jun 3, 2014 at 5:35 PM, Ista Zahn <istaz...@gmail.com> wrote: > Hi Frank, > > I don't think it is possible to state a general rule about which will > be faster. For example this > > system.time({ > for(i in 1:10000) { > x <- matrix(rnorm(10), ncol = 10) > y <- mean(x) > #rm(x) > z <- matrix(runif(10), ncol = 100) > #rm(z) > } > }) > > gets a lot slower if I uncomment the "rm()" lines, but this > > system.time({ > for(i in 1:5) { > x <- matrix(rnorm(10000000), ncol = 10) > y <- mean(x) > rm(x) > z <- matrix(runif(10000000), ncol = 100) > rm(z) > } > }) > > is slightly faster than it would be without the rm() lines. I think > you'll have to run a smaller version of the simulation both ways and > see which is faster. > > Best, > Ista > > On Tue, Jun 3, 2014 at 10:05 AM, Frank van Berkum > <frankieboy...@hotmail.com> wrote: >> Dear R-users, >> >> I'm working on a project in which many simulations have to be performed >> within functions. The simulations are quite time consuming. I thought that >> in general an empty memory is better for speed performance than a full >> memory. >> >> If I call a function which performs simulations within the function, than >> the memory will temporarily increase (while the function is executed and >> objects are created within the function), but as soon as the function is >> finished, temporarily objects are flushed. It seems as if it might be >> beneficial for speed performance to clear objects from the memory within the >> function if they are no longer needed in the remainder of the function. Does >> anyone know whether this is actually the case? >> >> Thanks in advance! >> >> Frank >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
